Traditionally, launch vehicles have carried one or two relatively large “primary” payloads to orbit with a lot of unused payload volume, because it is impractical to custom build a new launch vehicle (e.g., a rocket) for each payload to be launched into orbit. It has become usual practice within the satellite industry to pick a suitable launch vehicle that can carry just a bit more total mass and more total volume than is taken up by the primary payload(s) from a launch vehicle “shopping list.” The extra capacity of the launch vehicle is often called launch margin.
It is not desirable to waste the unused carrying capacity of the launch vehicle, and various schemes to take advantage of that extra capacity to carry one or more “secondary payloads,” have been devised to provide opportunities to launch small, inexpensive space missions. That is, these small inexpensive space missions rely on the ability to add “secondary payloads” on large launch vehicles to take advantage of unused lift capacity that may exist on a given launch vehicle once the needs of the primary payload have been met.
Conventional systems for incorporating one or more secondary payloads within a launch vehicle typically rely upon one or more dedicated special purpose deployment and avionics support boxes that are custom designed and fabricated on a per mission (i.e., per launch) basis. Custom design, fabrication, and integration of the special purpose deployment and avionics support boxes, however, is a costly (both in time and money) solution that conventionally must be repeated or recreated for each such launch. Each secondary payload also typically requires a unique set of launch vehicle services and interfaces. Development of payload-specific interface controls and definitions for each payload is time consuming and expensive for secondary payload mission programs.
For example, each secondary payload requires one or more services from the launch vehicle, such as (a) power for one or both of operations while attached to the secondary carrier and battery trickle charging prior to being deployed from the launch vehicle, (b) command and data handling, (c) deployment activation, and (d) video monitoring. Each secondary payload must therefore be integrated and tested with the launch vehicle prior to launch, which adds significant cost and time to preparation of the launch vehicle.